Category: stroke

Another study that found benefits to dog ownership. The study authors concluded that: "Our study provides evidence that dog owners are at a lower risk for ischemic stroke, hemorrhagic stroke and heart failure." This could be to daily exercise, or that dog ownership results in less stress or better psychosocial health, or even some other reason (perhaps dog owners are healthier to start with). Note: myocardial infarction (MI) is commonly known as a heart attack. From Medscape:

Middle-aged and older dog owners were less likely to die from cardiovascular heart disease (CVD) or all causes, and those who lived alone were less likely to have an MI (myocardial infarction) or stroke, during a decade of follow-up in a large study based on Swedish national registry data[1]. The findings suggest that "especially for those who live alone, dog ownership makes a significant difference . . . in health status," Dr Mwenya Mubanga (Uppsala University, Sweden) told Heartwire from Medscape.....

Dog owners get daily exercise from walking their dogs, and canine companions can reduce stress, which might explain these findings, the researchers speculate....Similarly, Dr Gang Hu (Pennington Biomedical Research, Baton Rouge, LA).....pointed out that the dog owners do more exercise (by walking their dogs), which may contribute to having a lower body weight, lower blood pressure, and possibly good lipid levels and a lower risk of diabetes—which may all act to lower mortality. Having a dog may also reduce the chances of having depression, which might partly explain the more striking findings in the people who lived alone, he added.

Since 2001, dog owners in Sweden have been required by law to register their dogs, and an estimated 83% of dogs were registered that year with the Swedish Board of Agriculture and/or the Swedish Kennel Club dog registries, Mubanga and colleagues explain. They examined the Swedish national registry data to see how dog ownership was related to new CVD events or mortality.....This included 162,091 dog owners (4.8% of the population) and 3,195,153 people who were not dog owners.

Dog owners who lived alone or with at least one child or adult were less likely to die of CVD or all causes during follow-up compared with those who did not own a dog, but the relationships were stronger for solitary dwellers. Among dog owners, solitary dwellers (but not others) were also significantly less likely to have an MI or stroke than people who did not have a dog.

The finding that the oral bacteria Streptococcus mutans, which isfound in 10% of the population, is linked with hemorrhagic strokes is big. S. mutans is found in tooth decay or cavities (dental caries). The researchers found a link with cnm-positive S. mutans with both intracerebral hemorrhage (ICH) and also with cerebral microbleeds. Some risk factors for strokes have long since been known, such as high blood pressure and advanced age, but then there are those hemorrhagic strikes that don't seem to fit the norm, with no apparent risk factors. Well, apparently the presence of cnm-positive S. mutans is one. My understanding of what cnm-positive S. mutans means is S. mutans bacteria that carries the collagen-binding Cnm gene. This bacteria can be found in a person's saliva and in dental plaque, and swabs of both were taken for this study.

This study builds on other studies that find a link between the bacteria Streptococcus mutans and a number of systemic diseases, including bacteremia, infective endocarditis and hemorrhagic stroke. The researchers of this latest study suggest that infection with cnm-positive S. mutanscauses constant inflammation (as shown by 2 inflammatory markers: CRP and fibrinogen), which then causes damage to blood vessels (endothelial damage) in the brain. Bottom line: take care of your teeth and gums. From Science Daily:

In a study of patients entering the hospital for acute stroke, researchers have increased their understanding of an association between certain types of stroke and the presence of the oral bacteria (cnm-positive Streptococcus mutans).

In the single hospital study, researchers at the National Cerebral and Cardiovascular Center in Osaka, Japan, observed stroke patients to gain a better understanding of the relationship between hemorrhagic stroke and oral bacteria. Among the patients who experienced intracerebral hemorrhage (ICH), 26 percent were found to have a specific bacterium in their saliva, cnm-positive S. mutans. Among patients with other types of stroke, only 6 percent tested positive for the bacterium.

Strokes are characterized as either ischemic strokes, which involve a blockage of one or more blood vessels supplying the brain, or hemorrhagic strokes, in which blood vessels in the brain rupture, causing bleeding.

The researchers also evaluated MRIs of study subjects for the presence of cerebral microbleeds (CMB), small brain hemorrhages which may cause dementia and also often underlie ICH. They found that the number of CMBs was significantly higher in subjects with cnm-positive S. mutans than in those without. The authors hypothesize that the S. mutans bacteria may bind to blood vessels weakened by age and high blood pressure, causing arterial ruptures in the brain, leading to small or large hemorrhages.

"This study shows that oral health is important for brain health. People need to take care of their teeth because it is good for their brain and their heart as well as their teeth," Friedland said. "The study and related work in our labs have shown that oral bacteria are involved in several kinds of stroke, including brain hemorrhages and strokes that lead to dementia."

Multiple research studies have shown a close association between the presence of gum disease and heart disease, and a 2013 publication by Jan Potempa, Ph.D., D.Sc., of the UofL School of Dentistry, revealed how the bacterium responsible for gum disease worsens rheumatoid arthritis. The cnm-negative S. mutans bacteria is found in approximately 10 percent of the general population, Friedland says, and is known to cause dental cavities (tooth decay). Friedland also is researching the role of oral bacteria in other diseases affecting the brain. http://www.nature.com/articles/srep20074

New research found that negative health effects - 35% increased risk of cardiovascular problems (coronary heart disease, heart attacks, strokes) are when the vitamin D levels are really low (under 15 nanograms per milliliter). Currently many doctors recommend optimal levels for health as somewhere between 35 to 40 ng/ml. One article in Medscape recommended 1,000 IU of vitamin D (preferably D3) daily to achieve this level. Or you can go outside in the sun for 15 to 20 minutes. From Science Daily:

A lack of vitamin D can result in weak bones. Recent studies also show that vitamin D deficiency is linked to more serious health risks such as coronary artery disease, heart attacks, and strokes. And now, a new study shows what level of deficiency puts someone at risk of developing these heart problems.Researchers at the Intermountain Medical Center Heart Institute in Salt Lake City have found that patients are fine from a heart standpoint, and may need no further treatment, if their vitamin D level is anywhere above 15 nanograms per milliliter.

"Although vitamin D levels above 30 were traditionally considered to be normal, more recently, some researchers have proposed that anything above 15 was a safe level. But the numbers hadn't been backed up with research until now," said J. Brent Muhlestein, MD, co-director of cardiovascular research at the Intermountain Medical Center Heart Institute, and lead researcher of the study.

The body naturally produces vitamin D as a result of exposure to the sun, and it's also found in a few foods -- including fish, fish liver oils, and egg yolks as well as some dairy and grain products. Those who don't have enough exposure to sunlight or vitamin D producing foods often have low vitamin D levels. Low levels are also attributed to race because people with dark skin have a natural protectant against ultraviolet light.

Dr. Muhlestein and his team have studied the effects of vitamin D on the heart for several years, looking at smaller numbers of patients. In this study, thanks to Intermountain Healthcare's vast clinical database, they were able to evaluate the impact of vitamin D levels on more than 230,000 patients. The 230,000 patients were split up into four groups (<15 ng/ml, 15-29, 30-44, ≥45) and were followed for the next three years by researchers who looked for major adverse cardiac events, including death, coronary artery disease, heart attacks, stroke, and incidents of heart or kidney failure.

Dr. Muhlestein found that for the nine percent of patients in the lower than 15 group, their risk of cardiovascular events increased by 35 percent compared to the other three groups, and the risks faced by the other three groups weren't very different from each other.

A nice summary article about the benefits and risks of coffee consumption. Summary of effects of drinking coffee: 1) May potentially increase blood pressure, but also may lower the risk for coronary disease, and protect against heart disease. 2) May cut stroke risk by as much as 25%, 3) Linked to improved glucose metabolism, reduced risk for type 2 diabetes, and promotion of weight loss in overweight patients. 4) May reduce the risk for several cancers. 5) Appears to slow the progression of dementia and Parkinson's disease. 6) A significantly decreased risk of developing depression. 7) Slows progression in alcoholic cirrhosis, hepatitis C, and NAFLD (non-alcoholic fatty liver disease). 8) May be beneficial in dry-eye syndrome, gout, and in preventing MRSA infection. 9) May increase blood pressure, anxiety, insomnia, tremor, withdrawal symptoms, and potential increased risk of glaucoma. From Medscape:

Earlier this year, the Dietary Guidelines Advisory Committee (DGAC) released a report[1] stating that up to five cups of coffee per day, or up to 400 mg of caffeine, is not associated with long-term health risks.Not only that, they highlighted observational evidence that coffee consumption is associated with reduced risk for several diseases, including type 2 diabetes, cardiovascular disease (CVD), and neurodegenerative disorders. The body of data suggesting that moderate coffee—and, in all likelihood, tea—consumption is not only safe but beneficial in a variety of mental and medical conditions is growing fast.

A 2012 study of over 400,000 people, published in the New England Journal of Medicine, reported that coffee consumption is associated with a 10% reduction in all-cause mortality at 13-year follow-up.... It's important to note that much of the evidence on the potential health effects of coffee, caffeine, and other foods and nutrients is associational and doesn't prove causality—observational investigations come with limitations and often rely on error-prone methods such as patient questionnaires. However, the sheer volume of existing observational data linking coffee and/or caffeine with various health benefits—as well as, in many cases, evidence of a dose response—suggests that the most widely consumed stimulant in the world has positive influences on our health.

Cardiovascular Disease:...However, when caffeine is ingested via coffee, enduring blood pressure elevations are small and cardiovascular risks may be balanced by protective properties.Coffee beans contain antioxidant compounds that reduce oxidation of low-density lipoprotein (LDL) cholesterol, and coffee consumption has been associated with reduced concentrations ofinflammatory markers. Moderate coffee intake is associated with a lower risk for coronary heart disease as far out as 10 years, and data suggest that an average of two cups per day protects against heart failure.

Cerebrovascular Disease and Stroke: The vascular benefits of coffee are not lost on the brain. According to a 2011 meta-analysis,consuming between one and six cups per day reportedly cut stroke risk by 17%. A 22%-25% risk reduction was seen in a large sample of Swedish women followed for an average of 10 years.

Diabetes:...Numerous studies have linked regular coffee drinking with improved glucose metabolism, insulin secretion, and a significantly reduced risk for diabetes. Most recently, findings from a long-term study published this year suggest that coffee drinkers are roughly half as likely to develop type 2diabetes as are nonconsumers, even after accounting for smoking, high blood pressure, and family history of diabetes.

Neurodegeneration: Beyond the short-term mental boost it provides, coffee also appears to benefit longer-term cognitive well-being. A 2012 study reported that patients with mild cognitive impairment and plasma caffeine levels of > 1200 ng/mL—courtesy of approximately three to five cups of coffee per day—avoided progression to dementia over the following 2-4 years.On a related note, a study from last year reported that caffeine consumption appears to enhance memory consolidation....Caffeinated coffee has long been thought to be neuroprotective in Parkinson disease (PD)....—as well as in multiple sclerosis.

Depression: A 2011 study suggests that a boost in coffee consumption might also benefit our mental health: Women who drank two to three cups of coffee per day had a 15% decreasedrisk for depression compared with those who drank less than one cup per week. A 20% decreased risk was seen in those who drank four cups or more per day. Newer work also suggests that regular coffee drinking may be protective against depression.

Liver Disease: The liver might help break down coffee, but coffee might protect the liver (in some cases). Evidence suggests that coffee consumption slows disease progression in patients with alcoholic cirrhosis and hepatitis C, and reduces the risk of developing hepatocellular carcinoma. A 2012 studyreported that coffee intake is associated with a lower risk for nonalcoholic fatty liver disease (NAFLD), while work published in 2014found that coffee protects against liver fibrosis in those with already established NAFLD.

And That's Not All…: An assortment of other research suggests that coffee intake might also relieve dry-eye syndrome by increasing tear production,reduce the risk for gout, and potentially fight infection.Coffee and hot tea consumption were found to be protective against one of the medical community's most concerning bugs, methicillin-resistant Staphylococcus aureus (MRSA). While it remains unclear whether the beverages have systemic antimicrobial activity, study participants who reported any consumption of either were approximately half as likely to have MRSA in their nasal passages.

And Finally, the Risks: As is often the case, with benefits come risks, and coffee consumption certainly has negative medical and psychiatric effects to consider. Besides the aforementioned potential increase in blood pressure, coffee can incite or worsen anxiety, insomnia, and tremor and potentially elevate glaucoma risk. Also, given the potential severity of symptoms, caffeine withdrawal syndrome is included as a diagnosis in the DSM-5.

Some recent studies looked at aspirin use and cancer and found that consistent use for a number of years (5 to 10 years) lowers the rate of a number of cancers, including colon cancer. However, the longer one takes daily aspirin - then harms start adding up, with a major one being gastrointestinal bleeding. NSAIDs (non-steroidal anti-inflammatory drugs) are also linked to lower rates of various cancers, but harms with long-term use are cardiovascular risks (stroke and heart attack). The first article discusses that many doctors think this lower cancer rate occurs because aspirin and NSAIDs lower inflammation, and as we know, inflammation is linked to cancer.

Research has shown that a regular dose of aspirin reduces the long-term risk of cancer in those who are overweight in an international study of people with a family history of the disease....They found that being overweight more than doubles the risk of bowel cancer in people with Lynch Syndrome, an inherited genetic disorder which affects genes responsible for detecting and repairing damage in the DNA. Around half of these people develop cancer, mainly in the bowel and womb. However, over the course of a ten year study they found this risk could be counteracted by taking a regular dose of aspirin.

Lots of people struggle with their weight and this suggests the extra cancer risk can be cancelled by taking an aspirin.This research adds to the growing body of evidence which links an increased inflammatory process to an increased risk of cancer. Obesity increases the inflammatory response. One explanation for our findings is that the aspirin may be suppressing that inflammation which opens up new avenues of research into the cause of cancer."

When they were followed up ten years later, 55 had developed bowel cancers and those who were obese were more than twice as likely to develop this cancer -- in fact 2.75 times as likely. Following up on patients who were taking two aspirins a day revealed that their risk was the same whether they were obese or not....What is surprising is that even in people with a genetic predisposition for cancer, obesity is also a driver of the disease.

The researchers believe the study shows that aspirin is affecting an underlying mechanism which pre-disposes someone to cancer and further study is needed in this area. Since the benefits are occurring before the very early stages of developing a tumour -- known as the adenoma carcinoma sequence -- the effect must be changing the cells which are predisposed to become cancerous in later years.

Artificial trans fats in foods are bad for health in so many ways: linked to increased risk of coronary heart disease, atherosclerosis, inflammation, and risk of early death. And even though the FDA is finally phasing out partially hydrogenated oils (because they have high levels of artificial trans fats) within the next 3 years, trans fats will still be found in foods (processed foods). How can this be? Well, trans fats are still allowed to be in foods that are labeled as 0 trans fats if it is less than .5 grams trans fats per serving (a loophole allows them to round downward to zero ). And according to research by Environmental Working Group (EWG), trans fats are being used by the food industry in undisclosed ways in amounts low enough to exploit the trans fat loophole. Besides partially hydrogenated oils, they are found in other types of refined oils, monoglycerides, diglycerides and other emulsifiers, and even in flavors and colors. So when you see ZERO trans fats on the label, it doesn't actually mean that it is zero trans fats. The problem is that over the course of a day, eating a number of foods and servings that have under .5 grams of trans fats adds up to levels that research now says has negative health effects!

So what can you do? Read ingredient lists on labels and try to avoid foods with the above mentioned ingredients: partially hydrogenated oils, emulsifiers, monoglycerides, diglycerides and other emulsifiers, artificial flavors, artificial flavors, and colors. Try to cut back or avoid foods that have ingredients that are not real foods - tough to do, but it can be done.

And the amazing part, saturated fats (such as butter) are NOT linked to early death and heart disease, but trans fat in foods is. Latest research, from Science Daily:

A study led by researchers at McMaster University has found that that trans fats are associated with greater risk of death and coronary heart disease, but saturated fats are not associated with an increased risk of death, heart disease, stroke, or Type 2 diabetes. The findings were published today by the British Medical Journal (BMJ)...."For years everyone has been advised to cut out fats. Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear," said de Souza.

Saturated fats come mainly from animal products, such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods.

Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease.

To help clarify these controversies, de Souza and colleagues analysed the results of 50 observational studies assessing the association between saturated and/or trans fats and health outcomes in adults....The team found no clear association between higher intake of saturated fats and death for any reason, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type 2 diabetes. However, consumption of industrial trans fats was associated with a 34 per cent increase in death for any reason, a 28 per cent increased risk of CHD mortality, and a 21 per cent increase in the risk of CHD.

Inconsistencies in the studies analysed meant that the researchers could not confirm an association between trans fats and type 2 diabetes. And, they found no clear association between trans fats and ischemic stroke. The researchers stress that their results are based on observational studies, so no definitive conclusions can be drawn about cause and effect.

Long-term air pollution can cause damage to the brain: covert brain infarcts ("silent strokes") and smaller brain volume (equal to one year of brain aging). The authors of a study looking at 900 men in the Boston area concluded that, on average, participants who lived in more polluted areas had the brain volume of someone 1 year older vs participants who lived in less polluted areas, and they also had a 46% higher risk for silent strokes. While the mechanisms of how air pollution may affect brain aging is unclear, the researchers think that inflammation resulting from the deposit of fine particles in the lungs is important. From Science Daily:

Air pollution, even at moderate levels, has long been recognized as a factor in raising the risk of stroke. A new study led by scientists from Beth Israel Deaconess Medical Center and Boston University School of Medicine suggests that long-term exposure can cause damage to brain structures and impair cognitive function in middle-aged and older adults. Writing in the May 2015 issue of Stroke, researchers who studied more than 900 participants of the Framingham Heart Study found evidence of smaller brain structure and of covert brain infarcts, a type of "silent" ischemic stroke resulting from a blockage in the blood vessels supplying the brain.

The study evaluated how far participants lived from major roadways and used satellite imagery to assess prolonged exposure to ambient fine particulate matter, particles with a diameter of 2.5 millionth of a meter, referred to as PM2.5. These particles come from a variety of sources, including power plants, factories, trucks and automobiles and the burning of wood. They can travel deeply into the lungs and have been associated in other studies with increased numbers of hospital admissions for cardiovascular events such as heart attacks and strokes.

Study participants were at least 60 years old and were free of dementia and stroke. The evaluation included total cerebral brain volume, a marker of age-associated brain atrophy; hippocampal volume, which reflect changes in the area of the brain that controls memory; white matter hyperintensity volume, which can be used as a measure of pathology and aging; and covert brain infarcts.

The study found that an increase of only 2µg per cubic meter in PM2.5, a range commonly observed across metropolitan regions in New England and New York, was associated with being more likely to have covert brain infarcts and smaller cerebral brain volume, equivalent to approximately one year of brain aging...."This is concerning since we know that silent strokes increase the risk of overt strokes and of developing dementia, walking problems and depression."

After reading this article, I looked over my last year's posts and realized that the recent studies posted all found that eating fish showed health benefits (and they did not look at supplements). Once again, a food shows benefits while the supplement is debatable. Current advice: try to eat fish at least twice a week. From the NY Times:

Fish oil is now the third most widely used dietary supplement in the United States, after vitamins and minerals, according to a recent report from the National Institutes of Health. At least 10 percent of Americans take fish oil regularly, most believing that the omega-3 fatty acids in the supplements will protect their cardiovascular health. But there is one big problem: The vast majority of clinical trials involving fish oil have found no evidence that it lowers the risk of heart attack and stroke.

From 2005 to 2012, at least two dozen rigorous studies of fish oil were published in leading medical journals, most of which looked at whether fish oil could prevent cardiovascular events in high-risk populations. These were people who had a history of heart disease or strong risk factors for it, like high cholesterol, hypertension or Type 2 diabetes. All but two of these studies found that compared with a placebo, fish oil showed no benefit.

In theory at least, there are good reasons that fish oil should improve cardiovascular health. Most fish oil supplements are rich in two omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — that can have a blood-thinning effect, much like aspirin, that may reduce the likelihood of clots. Omega-3scan also reduce inflammation, which plays a role in atherosclerosis. And the Food and Drug Administration has approved at least three prescription types of fish oil — Vascepa, Lovaza and a generic form — for the treatment of very high triglycerides, a risk factor for heart disease.But these properties of omega-3 fatty acids have not translated into notable benefits in most large clinical trials.

Like many cardiologists, Dr. Stein encourages his patients to avoid fish oil supplements and focus instead on eating fatty fish at least twice a week, in line with federal guidelines on safe fish intake, because fish contains a variety of healthful nutrients other than just EPA and DHA. “We don’t recommend fish oil unless someone gets absolutely no fish in their diets,” Dr. Stein said.

But some experts say the case for fish oil remains open. Dr. JoAnn Manson, the chief of preventive medicine at Brigham and Women’s Hospital in Boston, said the large clinical trials of fish oil focused only on people who already had heart disease or were at very high risk. Fish oil has also been promoted for the prevention of a variety of other conditions, including cancer, Alzheimer’s and depression. Dr. Manson is leading a five-year clinical trial, called the Vital study, of 26,000 people who are more representative of the general population. Set to be completed next year, it will determine whether fish oil and vitamin D, separately or combined, have any effect on the long-term prevention of heart disease, Type 2 diabetes, and other diseases in people who do not have many strong risk factors.

Dr. Manson says that although she recommends eating fatty fish first, she usually does not stop people from taking fish oil, in part because it does not seem to have major side effects in generally healthy people. “But I do think people should realize that the jury is still out,” she said, “and that they may be spending a lot of money on these supplements without getting any benefit.”

Two studies that found a link with air pollution and health effects.The first found a narrowing of the carotid arteries (that bring blood to brain). This narrowing (stenosis) occurs prior to strokes. While this could be explained by other factors (for example, by especially poor diets or cigarette smoking), the link between high air pollution and heart attacks and strokes has been noted since the 1950s. From Medical Xpress:

Air pollution has been linked to a dangerous narrowing of neck arteries that occurs prior to strokes, according to researchers at NYU Langone Medical Center. The scientists analyzed medical test records for more than 300,000 people living in New York, New Jersey or Connecticut.They found that people living in zip codes with the highest average levels of fine-particulate-matter pollution were significantly more likely to show signs of narrowing (stenosis) in their internal carotid arteries, compared to those living in zip codes with the lowest pollution levels.

Fine particulate matter pollutants, also called "PM 2.5 pollutants," are particulates with diameters less than 2.5 millionths of a meter. They are mostly by-products of combustion engines and burning wood. "We spend a lot of time thinking about traditional risk factors for stroke such as high blood pressure, cholesterol, diabetes and smoking—but our data underscore the possibility that everyday air pollution may also pose a significant stroke risk," said senior investigator Jeffrey S. Berger, MD, an assistant professor in NYU Langone Medical Center in the Department of Medicine, Leon H. Charney Division of Cardiology.

Medical researchers have noticed since the 1950s that episodes of high air pollution can bring temporary jumps in local heart attack and stroke cases. More recent studies have linked heart attack and stroke risks to long-term pollution exposures as well, including PM 2.5 exposures.

The two internal carotid arteries are situated on either side of the neck and provide most of the brain's blood supply. Strokes often result when accumulated plaque breaks off from a narrowed section of an internal carotid artery and blocks smaller vessels in the brain.

In the study, the carotid narrowing data came from vascular ultrasound tests performed on 307,444 tri-state area residents during 2003-2008 by Life Line Screening, a leading community-based health screening company focused on evaluating risk factors for vascular disease...The researchers' analysis showed that subjects in the top fourth of tri-state zip codes, ranked by average PM 2.5 levels,were about 24 percent more likely than those in the bottom quarter to have shown signs of stenosis—defined as a narrowing by at least half—in eitherinternal carotid artery.

"Our study was a population study, so it can't establish cause and effect, but it certainly suggests the hypothesis that lowering pollution levels would reduce the incidence of carotid artery stenosis and stroke," says Dr. Newman. Scientists aren't yet sure how air pollution contributes to vascular disease. Studies have indicated that it may do so in part by causing adverse chemical changes to cholesterol in the blood, by promoting inflammation, and by making blood platelets more likely to form clots."

It has long been known that diesel exhaust has negative health effects. From Science Daily:

Researchers have, for the first time, shown how exhaust pollution from diesel engines is able to affect nerves within the lung...Diesel exhaust is a significant component of urban air pollution, containing a complicated mixture of gases and airborne particles. "Studies have shown that exposure to these diesel particles is associated with harmful health effects," says Mr. Robinson. "These particles are very small -- down to 20 nanometres in diameter -- and are therefore not only invisible to the naked eye, but can penetrate deep into the lungs.

Can you have too high levels of vitamin D? The researchers themselves say that the results show there is a J shaped curve linking vitamin D levels in the blood and mortality - both too high and too low levels are linked to higher levels of mortality. From Science Daily:

The level of vitamin D in our blood should neither be too high nor to low. Scientists have now shown that there is a connection between high levels of vitamin D and cardiovascular deaths.

In terms of public health, a lack of vitamin D has long been a focal point. Several studies have shown that too low levels can prove detrimental to our health. However, new research from the University of Copenhagen reveals, for the first time, that also too high levels of vitamin D in our blood is connected to an increased risk of dying from a stroke or a coronary.

"We have studied the level of vitamin D in 247,574 Danes, and so far, it constitutes the world's largest basis for this type of study. We have also analysed their mortality rate over a seven-year period after taking the initial blood sample, and in that time 16,645 patients had died. Furthermore, we have looked at the connection between their deaths and their levels of vitamin D," Professor at the Department of Clinical Medicine, Peter Schwarz explains.

The conclusion is clear: the study confirms that there is indeed a correlation between mortality rates and too low levels of vitamin D, but the new thing is that the level of vitamin D can also be too high.

"If your vitamin D level is below 50 or over 100 nanomol per litre, there is an greater connection to deaths. We have looked at what caused the death of patients, and when numbers are above 100, it appears that there is an increased risk of dying from a stroke or a coronary. In other words, levels of vitamin D should not be too low, but neither should they be too high. Levels should be somewhere in between 50 and 100 nanomol per litre, and our study indicates that 70 is the most preferable level," Peter Schwartz states.